Food Safety and Inspection
Service
United States Department of Agriculture
Washington, D.C. 20250-3700

Consumer Education and Information

July 1998
Contact Information Slightly Revised May 2000

The Color of Meat and Poultry

Ive just opened a package of fresh chicken and the skin
looks blue. Is it safe to use?

My package of ground beef is dark in the center. Is this old meat?

The turkey was cooked according to the directions, but the breast meat
is pink. Will it make us sick?

These are just a few of the many questions received at the U.S.
Department of Agricultures Meat and Poultry Hotline concerning the color of meat and
poultry. Color is important when meat and poultry are purchased, stored, and cooked. Often
an attractive, bright color is a consideration for the purchase. So, why are there
differences in the color and what do they mean? Listed below are some questions and
answers to help you understand the color differences.

1. What factors
affect the color of meat and poultry?

Myoglobin, a protein, is
responsible for the majority of the red color. Myoglobin doesn't circulate in the blood
but is fixed in the tissue cells and is purplish in color. When it is mixed with oxygen,
it becomes oxymyoglobin and produces a bright red color. The remaining color comes from
the hemoglobin which occurs mainly in the circulating blood, but a small amount can be
found in the tissues after slaughter.

Color is also influenced by the age of the animal, the species, sex,
diet, and even the exercise it gets. The meat from older animals will be darker in color
because the myoglobin level increases with age. Exercised muscles are always darker in
color, which means the same animal can have variations of color in its muscles.

In addition, the color of meat and poultry can change as it is being
stored at retail and in the home (see explanation in question 5). When safely stored in
the refrigerator or freezer, color changes are normal for fresh meat and poultry.

2. Does a change in color
indicate spoilage?

Change in color alone does not
mean the product is spoiled. Color changes are normal for fresh product. With spoilage
there can be a change in color -- often a fading or darkening. In addition to the color
change, the meat or poultry will have an off odor, be sticky or tacky to the touch, or it
may be slimy. If meat has developed these characteristics, it should not be used.

3. If the color of meat and poultry changes
while frozen, is it safe?

Color changes, while meat and poultry are
frozen, occur just as they do in the refrigerator. Fading and darkening, for example, do
not affect their safety. These changes are minimized by using freezer-type wrapping and by
expelling as much air as possible from the package.

4. What are the white
dried patches on frozen meat and poultry?

The white dried patches indicate freezer burn.
When meat and poultry have been frozen for an extended period of time or have not been
wrapped and sealed properly, this will occur. The product remains safe to eat, but the
areas with freezer burn will be dried out and tasteless and can be trimmed away if
desired.

THE COLOR OF MEAT

5. When displayed at the
grocery store, why is some meat bright red and other meat very dark in color?

Optimum surface color of fresh meat (i.e., cherry-red for beef; dark cherry-red for
lamb; grayish-pink for pork; and pale pink for veal) is highly unstable and short-lived.
When meat is fresh and protected from contact with air (such as in vacuum packages), it
has the purple-red color that comes from myoglobin, one of the two key pigments
responsible for the color of meat. When exposed to air, myoglobin forms the pigment,
oxymyoglobin, which gives meat a pleasingly cherry-red color. The use of a plastic wrap
that allows oxygen to pass through it helps ensure that the cut meats will retain this
bright red color. However, exposure to store lighting as well as the continued contact of
myoglobin and oxymyoglobin with oxygen leads to the formation of metmyoglobin, a pigment
that turns meat brownish-red. This color change alone does not mean the product is spoiled
(see explanation in question 2).

6. Why is pre-packaged ground beef
red on the outside and sometimes grayish-brown on the inside?

These color differences do not indicate that the
meat is spoiled or old. As discussed earlier, fresh cut meat is purplish in color. Oxygen
from the air reacts with meat pigments to form a bright red color which is usually seen on
the surface of ground beef purchased in the supermarket. The interior of the meat may be
grayish-brown due to the lack of oxygen penetrating below the surface.

7. A beef roast has darkened in
the refrigerator, is it safe?

Yes, it is safe. The darkening is due to
oxidation, the chemical changes in myoglobin due to the oxygen content. This is a normal
change during refrigerator storage.

8. Can cooked ground beef still be
pink inside?

Yes, ground beef can be pink inside after it is
safely cooked. The pink color can be due to a reaction between the oven heat and
myoglobin, which causes a red or pink color. It can also occur when vegetables containing
nitrites are cooked along with the meat. Because doneness and safety cannot be judged by
color, it is very important to use a meat thermometer when cooking ground beef. To be sure
all harmful bacteria are destroyed, cook all ground beef products to an internal
temperature of 160 ° F throughout.

9. What causes iridescent colors
on meats?

Meat
contains iron, fat, and other compounds. When light hits a slice of meat, it splits into
colors like a rainbow. There are various pigments in meat compounds that can give it an
iridescent or greenish cast when exposed to heat and processing. Wrapping the meat in
airtight packages and storing it away from light will help prevent this situation.
Iridescence does not represent decreased quality or safety of the meat.

10. What causes
grayish or green color on cured meats?

Exposure to light and oxygen causes oxidation to
take place, which causes the breaking down of color pigments formed during the curing
process. Chemicals in the cure and oxygen, as well as energy from ultraviolet and visible
light, contribute to both the chemical breakdown and microbial spoilage of the product.
Cure, such as nitrite, chemically changes the color of muscle. Curing solutions are
colored in order to distinguish them from other ingredients (such as sugar or salt) used
in fresh and cured meat products. For example, cured raw pork is gray, but cured cooked
pork (e.g., ham) is light pink.

THE COLOR OF POULTRY

11. What is the usual color of raw poultry?

Raw poultry can vary from a bluish-white to yellow. All of these colors
are normal and are a direct result of breed, exercise, age, and/or diet. Younger poultry
has less fat under the skin, which can cause the bluish cast, and the yellow skin could be
a result of marigolds in the feed.

12. What causes the differences
in color of raw ground poultry?

Ground poultry varies in color according to
the part being ground. Darker pink means more dark meat was used and a lighter pink means
more white meat was included (or skin was included). Ground poultry can contain only
muscle meat and skin with attached fat in proportion to the whole bird.

13. What causes dark
bones in cooked poultry?

Darkening
of bones and meat around the bones occurs primarily in young (6-8 weeks) broiler-fryer
chickens. Since the bones have not calcified or hardened completely, pigment from the bone
marrow seeps through the bones and into the surrounding area. Freezing can also contribute
to this darkening. This is an aesthetic issue and not a safety one. The meat is safe to
eat when all parts have reached at least 160 ° F.

14. What color is
safely cooked poultry?

Safely cooked poultry can vary in color from
white to pink to tan. When the temperature of the poultry as measured in the thigh has
reached 180 ° F, there is usually no other site in the bird lower than the safe
temperature of 160 ° F. Check the temperature in several locations, being sure to include
the wing joint. All the meatincluding any that remains pinkis safe to eat as
soon as all parts reach at least 160 ° F.

15. Why is some
cooked poultry pink?

Chemical changes occur during cooking. Oven gases in a heated gas or
electric oven react chemically with hemoglobin in the meat tissues to give it a pink
tinge. Often meat of younger birds shows the most pink because their thinner skins permit
oven gases to reach the flesh. Older animals have a fat layer under their skin, giving the
flesh added protection from the gases. Older poultry may be pink in spots where fat is
absent from the skin. Also, nitrates and nitrites, which are often used as preservatives
or may occur naturally in the feed or water supply used, can cause a pink color.

16. If fully cooked smoked
poultry is pink, is it safe?

Poultry grilled or smoked outdoors can be pink, even when all parts
have attained temperatures well above 160 ° F. There may be a
pink-colored rim about one-half inch wide around the outside of the cooked product.
Commercially prepared, smoked poultry is usually pink because it is prepared with natural
smoke and liquid smoke flavor. Federal regulations require all processed poultry to be
cooked to at least 160 ° F instantly, or to an equivalent
level of safety attained by this minimum temperature requirement.

For additional food safety information about meat, poultry, or eggs, call the
toll-free USDA Meat and Poultry Hotline at 1 (800) 535-4555; Washington, DC (202)
720-3333; TTY: 1 (800) 256-7072. It is staffed by home economists, dietitians, and food
technologists weekdays from 10 a.m. to 4 p.m. Eastern time, year round. An extensive
selection of food safety recordings can be heard 24 hours a day using a touch-tone phone.